Neural progenitor migration is an important process for the proper development and maintenance of the nervous system. Derived from proliferative zones within the brain, neural progenitors migrate to specific destinations guided by various extracellular cues. Exposure to neurotoxicants during development can interfere with neural progenitor migration and lead to nervous system defects. Today there are several in vitro assays to measure cell migration, yet a simple thaw and use product/assay using representative human neural cells is not available. Recent publications advocate the development of in vitro cell culture systems to identify and prioritize potential human developmental neurotoxicants (drugs and environmental). Animal testing is expensive and time consuming. Also, the need for human neural migration assays has been expressed by federal agencies and companies (see letter of support). The demand and potential volume for such a product is largely based on the knowledge that human and animal populations are being exposed to >80,000 commercial chemicals that have not been tested for neurotoxicity. This proposal focuses on development of a cellular assay system featuring cryopreserved adherent cells on ready to use multi-well plates, combining ArunA Biomedical's patented human neural cells and Tissue Testing Technologies' cryopreservation technology. We will develop a thaw-and-use cryopreserved migration high content assay plate for human neural progenitor cells. We will adapt and optimize CryoPlateTM technology for pre-plated migration assays. The cryopreservation technology consists of a patented method to maintain adherent cells attached to their substrate during cryopreservation in 96 and 384 well plates. There are two tasks, first, using various processes and materials, example being rate of freezing and extracellular matrix we will optimize the cryopreservation technique. Second, compare post-thaw migration of neural progenitor cells on cryopreserved adherent assay plates with assay plates prepared with standard cryopreserved cell suspensions plated prior to assay implementation. Ultimately, this technology will impact the prioritization of chemicals for more extensive toxicological evaluation, minimizing animal utilization, in support of more predictive models of in vivo biological responses